While much world attention has unsurprisingly been focused on the sound and fury coming out of Washington over the debt ceiling and the possible default, the diplomatic tectonic plates seem to be moving in a favourable direction with a speed which has attracted little attention but which may have major long-term implications.

A few short weeks ago, we looked to be on the brink of another violent explosion in the Middle East as President Barack Obama geared up to launch punitive, limited surgical strikes on President Bashar al-Assad of Syria’s forces and infrastructure. (We know from drone strikes how apparently surgically targeted attacks can go horrendously awry.)

A combination of a surprise negative vote in the UK parliament, the slowly dawning resolution that the US Congress – having been consulted – was not going to vote to authorise air strikes, and adroit footwork by the Russian foreign minister, Sergey Lavrov, has led to a radically different state of affairs.

Inspectors from the Nobel Peace prize-winning Organisation for the Prohibition of Chemical Weapons (OPCW) are busy destroying the Assad chemical weapon inventory, or at least as much of it as lies in territory controlled by the regime, and there is even a serious prospect of convening talks with the warring parties next month in Geneva to try to find a political solution.

It would be foolish to get carried away with too much optimism. Yet talks in Geneva bringing Russia back into play may be the useful counterbalance in Middle East negotiations which has been largely absent in recent years and which has been a factor in the until-now sclerotic state of the talks on resolving the Syria conflict and indeed the wider and even more toxic Arab-Israel question.

Regional superpowerThere are of course major problems both on the ground and politically. Iran as a regional superpower with legitimate interests in what is happening in Syria needs to be involved, yet its presence might prompt a walkout by the overwhelmingly Sunni rebel movement.

Then Assad sees no reason to go quietly into retirement or exile. At the moment, he probably believes the civil war has turned in his favour.

He certainly will not agree to be pushed out just because western powers proclaim that he has no further legitimacy. And it may be that a unified Syria is no longer sustainable.

The whole of the Levant might Balkanise. Its borders were only cobbled together to reflect planned spheres of influence during the first World War by two British and French diplomats, Sir Mark Sykes and François Georges-Picot. Not just Syria but Iraq, with Kurdish separatists, and Lebanon, deeply divided confessionally, are highly fissile.

A more immediate worry is the fact that Syrian rebel forces control many of the sites where chemical weapons are held and have so far been reluctant to allow the inspectors access to destroy the stocks. There is a very real fear that the jihadists, particularly the Islamic State of Iraq and al-Sham and the al-Nusra Front, increasingly in the ascendant in rebel ranks and with active links to al-Qaeda, may already have helped themselves to supplies of sarin and VX, another nerve gas 10 times more toxic than sarin.

This would take the threat from international terrorism to new heights. Imagine the effect of introducing, say, sarin into the New York subway.

While this is a bleak scenario indeed, there is better news on another long-standing issue, the possibility of Iran producing nuclear weapons.

After 10 years of fairly futile negotiations, and increasing threats from Israel to eliminate by force Iran’s capability for building a nuclear weapon, we are suddenly in new territory.

New Iranian president Hassan Rouhani’s charm offensive in New York last month (culminating in his telephone conversation with Obama) has been followed up concretely by his foreign minister, Mohammad Javad Zarif. In the last few days, he has used a PowerPoint presentation to attempt to convince the P5+1 (the five permanent UN Security Council members plus Germany) that Iran has a roadmap to resolve the issue in a realistic but short timescale.

The mood music was surprisingly good and substantive negotiations are expected within a few weeks.

One US official is quoted as saying: “I have never had such intense, detailed, straightforward, candid conversations with the Iranian delegation before”.

Both sides can be expected to offer confidence-building measures which may lead to some sanctions relief for the particularly hard-pressed Iranian economy.

Obama can expect some robust opposition to any softening of sanctions from those in US politics who take their cue on these matters from Israel’s prime minister, Binyamin Netanyahu.

Two-way streetBut getting Iran to make the necessary concessions will require reciprocity, however unpalatable to Washington hard-liners and Israel.

What is clear is that Iran needs sanctions relief urgently.

To that end, Rouhani has been given a window of opportunity which may only last a few months by Iran’s supreme leader, the unelected Ayatollah Khamenei.

If Rouhani fails to make a breakthrough leading to the lifting of (some) sanctions and a revival of the Iranian economy, we can expect a return to, as it were, the bunker in Iran, and a determination to press ahead with a nuclear programme which gives every sign of being capable of producing a bomb in the next year or so. Israel will not sit idly by.

The stage would therefore be set for a Middle East conflagration which would make Syria look like a picnic.

So the stakes for all concerned are very high. There has never been a better time for diplomacy to work.

It should be given every opportunity to do so.

Sir Ivor Roberts, president of Trinity College, Oxford, was British ambassador to Ireland from 1999 to 2003

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